REGULATORYRFK Jr.: 14 peptides returning to Category 1 — FDA advisory committee July 2026TRENDINGHexarelin: ↑↑ Surging ��� Trends score 100 as of May 2026UPDATESemaglutide and tirzepatide compounding ended — shortage resolved Feb/May 2025REGULATORYBPC-157, TB-500, thymosin alpha-1, CJC-1295, ipamorelin: expected Category 1 reclassification pendingEVENTpep-talk con ��� First US Peptide Convention · August 2026 · Anaheim CAFDAFDA advisory committee meetings scheduled: late July 2026REGULATORYRFK Jr.: 14 peptides returning to Category 1 — FDA advisory committee July 2026TRENDINGHexarelin: ↑↑ Surging ��� Trends score 100 as of May 2026UPDATESemaglutide and tirzepatide compounding ended — shortage resolved Feb/May 2025REGULATORYBPC-157, TB-500, thymosin alpha-1, CJC-1295, ipamorelin: expected Category 1 reclassification pendingEVENTpep-talk con ��� First US Peptide Convention · August 2026 · Anaheim CAFDAFDA advisory committee meetings scheduled: late July 2026

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Peptide Library

Triptorelin

Trelstar / Decapeptyl / GnRH agonist

Sexual Health

Triptorelin is a synthetic GnRH agonist (decapeptide analog) that is approximately 100 times more potent than native GnRH, used primarily for sustained suppression of the reproductive axis. It is FDA-approved as Trelstar for the treatment of advanced prostate cancer through chemical castration via continuous GnRH receptor stimulation. In research and clinical contexts, it is also used in post-cycle therapy (PCT) protocols to restart the hypothalamic-pituitary-gonadal axis after anabolic steroid use.

Mechanism of Action

Potent GnRH agonist with greatly enhanced receptor binding affinity. Initial administration causes a flare of LH/FSH and testosterone. Continuous administration leads to profound suppression of the HPG axis via pituitary GnRH receptor downregulation.

Research Protocols

For research purposes only. Not medical advice.

Research protocols use 50-100mcg as a single dose for hormonal reset. Depot formulations (3.75mg monthly, 11.25mg quarterly, 22.5mg semi-annual) used for sustained suppression. Anti-suppressive protocols use micro-dosing.

Research Notes

Clinical Research Status

Triptorelin holds FDA approval for advanced prostate cancer (Trelstar, in depot formulations of 1-month, 3-month, and 6-month durations) and is approved in Europe for additional indications including endometriosis and precocious puberty. Research has explored single-dose triptorelin (100 mcg) for HPG axis recovery following androgen-induced hypogonadism. The European Medicines Agency also recognizes its use in assisted reproduction protocols for ovulation triggering.

Key Published Findings

A landmark 2010 study (Mourelatos et al.) demonstrated that a single 100 mcg injection of triptorelin could restore gonadotropin levels in men with anabolic steroid-induced hypogonadism within 1-2 weeks. In prostate cancer, depot formulations reduce testosterone to castrate levels (<50 ng/dL) within 2-4 weeks after an initial transient surge. Clinical trials confirm sustained efficacy for testosterone suppression over 6-12 month treatment periods.

Safety Profile

The initial GnRH agonist flare (temporary testosterone increase in the first 1-2 weeks) can exacerbate prostate cancer symptoms and typically requires concurrent anti-androgen coverage. Long-term use causes expected effects of hypogonadism: hot flashes, decreased libido, bone density loss, and metabolic changes. In PCT use, the single low-dose protocol (100 mcg) has minimal reported adverse effects due to the brief exposure duration.

Comparison to Related Compounds

Compared to other GnRH agonists (leuprolide, goserelin), triptorelin has similar efficacy for testosterone suppression but differs in formulation options and pharmacokinetics. For PCT purposes, triptorelin's single-dose protocol contrasts with the multi-week SERM-based approaches using clomiphene or tamoxifen. Unlike gonadorelin which stimulates at pulsatile doses, triptorelin's continuous receptor activation leads to desensitization and suppression after the initial stimulatory phase.

Community Observations

In PCT contexts, the single 100 mcg triptorelin injection protocol has gained popularity as a rapid HPG axis restart option, though evidence remains limited to small studies. Practitioners caution that doses above 100 mcg risk prolonged suppression rather than recovery, making precise dosing critical. Most PCT experts recommend combining triptorelin with SERMs rather than using it as a standalone restart agent for optimal recovery outcomes.

Half-Life

~3-5 hours (daily form); 28 days (depot)

Reconstitution

Sterile water for injection

Storage

Lyophilized

Refrigerate 2-8C.

Reconstituted

Use immediately after reconstitution for depot forms.

US Legal Status

FDA-approved (Rx only)

Also Known As

TrelstarDecapeptylGnRH agonist

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